1. Field of the Invention
This invention relates to a bakery shortening substitute that is an emulsion having a lipid phase and an aqueous phase, the aqueous phase containing a gelling agent that is konjac. This invention also relates to the emulsion preparation method and bakery products that contain the emulsion as a reduced-fat shortening substitute.
2. Background Information
A recent trend in the food industry is the introduction of reduced fat or no fat versions of many fat-containing food products, such as bakery goods. Bakery food products include cakes, cookies, pastries, breads, and the like. Baked goods are prepared from batters or doughs that contain, in addition to flour and sugar, lipids such as fats and/or oils, i.e., liquid fats, often in combination with emulsifiers. Many bakery products require a relatively large proportion of fat, e.g., introduced as shortening and/or butter or the like. Cake batter, for example, can contain 20-35 weight percent shortening.
Elimination or replacement of a portion of the fat content in bakery food products can lead to dramatic reductions in fat content, but such reduced fat levels often have adverse consequences affecting the taste, texture and volume of the baked goods.
The functions of the fat component in bakery goods are several:
provide shortened or flaky crumb structure; PA1 provide moistness and lubricity PA1 stabilize foam (aeration) formed during baking PA1 provide firmness and clean bite PA1 reduce product stickiness during the baking process.
Satisfactory systems for replacing the fat component in baked goods must not only be functional, e.g., providing shortened crumb structure and foam stabilization, but also provide desirable sensory characteristics, e.g., moistness, tenderness, good bite, lubricity, and cohesiveness.
Reduced fat and nonfat baked goods, such as cakes, which are presently being sold typically exhibit one or more of the following undesirable attributes: dryness, gumminess (bails up in the mouth), coarse texture, or no lubricity.
Numerous fat substitutes have been described in the literature for use in replacing the oil or fat in fat-containing foods, like salad oils and dressings, mayonnaises, nondairy spreads and desserts like baked goods. An introductory overview to current techniques for reducing the fat content of baked foods is presented by McWand, "The Low-Fat Challenge" in Baking & Snack, August 1993, pp. 37-42.
Hydrocolloid gums have been used to reduce fat levels by allowing increased water contents in the lowered fat foods, the hydrocolloid serving to bind water. Xanthan gum is the most widely used hydrocolloid gum for this purpose, but other hydrocolloids such as carboxymethylcellulose, pectin, alginate, carrageenan, gum tragacanth and locust bean gum have been proposed for this use. Excessive use of these hydrocolloids can lead to gumminess in bakery food products; this characteristic limits the extent to which increased water levels (bound with these products) can replace the fat content of high fat bakery foods. Microcrystalline cellulose, which can serve as the functional equivalent of a hydrocolloid gum, has also been recommended as a fat replacer in reduced fat foods. The use of liquid shortenings as replacements in bakery goods for semi-solid, plastic-consistency shortenings, e.g., vegetable shortenings produced by hydrogenation of vegetable oil, is described by Knightly in "Surfactants in Baked Foods: Current Practice and Future Trends", Cereal Food World, 33:405-412 (1988). Semisolid, plastic-consistency shortenings continue to be a preferred choice in commercial bakery products. A need exists with lowered fat or nonfat baked goods for a shortening substitute that can replace conventional high fat shortenings, on a one-to-one basis, while still providing the processing characteristics of the high fat shortenings that it replaces.
Emulsion technology has been utilized to make lowered fat food products. U.S. Pat. No. 5,178,897 issued to Tanaka et al. describes a water-in-oil emulsion composition for baked food products, white bread being exemplified. The emulsion contains a sizing agent that may be starch, guar gum, carrageenan, alginates or pectin. U.S. Pat. No. 5,332,595 issued to Gaonkar describes water/oil/water and oil/water/oil emulsions that are useful in salad dressings, spreads, sauces, frozen desserts and the like. The emulsion contains a gel forming composition that may be a gellable polysaccharide such as alginate, carrageenan, chitosan or gellan that is present as a gelatinous layer at the internal water/oil interface. The internal aqueous phase may also contain a thickener gum such as xanthan, gum arabic, carob bean gum, gum tragacanth, guar gum or the like. U.S. Pat. No. 5,338,561 issued to Campbell et al. describes a water continuous emulsion that contains a gelling polysaccharide like guar, carrageenan, pectin, alginate, gellan and furcellaran, for use in nondairy creams, dressings and mayonnaises.
Konjac glucomannan is another hydrocolloid gel that has been mentioned in publications that describe its use as a thickener or gelling agent in various food applications.
U.S. Pat. No. 4,427,704 issued to Cheney et al. describes thermo-reversible or thermo-irreversible gels containing carrageenan and a glucomannan such as konjac, and the thermo-irreversible gels are described as useful in food products resistant to structural breakdown upon heating.
U.S. Pat. No. 4,582,714 issued to Ford et al. describes ungelled processed food product stabilized and/or thickened by at least one glucomannan, such as konjac glucomannan. Suitable food products are those with thickened and/or stabilized (but not gelled) emulsions and the examples include ice cream, whipping cream, meringues, cheese spreads, cheese slices and milk drinks.
U.S. Pat. No. 4,676,976 issued to Toba et al. describes a konjac mannan-containing reversible gel that also contains xanthan gum, useful in foodstuffs that are in a gel state at room or chilled temperatures (e.g., jelly), foodstuffs that are converted to a liquid-to-semisolid state by heating (eg., soup, meltable cheese) and foodstuffs in which solid, paste and liquid states are co-present (e.g., minced meat dumplings).
U.S. Pat. No. 4,746,528 issued to Prest et al. describes a gellable system containing gellan, xanthan gum and a galactomannan or glucomannan gum that produces a gel in combination with xanthan, especially carob, tara, cassia or konjac gum. The gelling system is described as having application to a wide variety of human or animal foods, especially in pasteurized or sterilized food products.
U.S. Pat. No. 4,894,250 issued to Musson et al. describes thermo-irreversible aqueous gels containing xanthan and a glucomannan such as konjac, useful in food products such as minced meat.
An object of the present invention is a shortening substitute that replaces conventional shortening in bakery products and that also provides the physical and sensory characteristics of conventional shortening in high fat bakery products.